Apparatus for spinning artificial threads



H. SCHRAQDER March 24, 1970 APPARATUS FOR SPINNING ARTIFICIAL THREADS Filed April 28. 1966 FIG! m w R I N VEN TOR Y HANSGEORG SCHRADER B Y 35 Q Mf ATT YS United States Patent Int. Cl. B29r 3/03 US. Cl. 188 3 Claims ABSTRACT OF THE DISCLOSURE Apparatus for spinning threads from viscous spinning compositions in which means are provided for changing a filter in the equipment without interrupting the flow of composition to the spinning nozzle and without risking the addition of air or decomposed products to the spun material. At least two lines are provided between a supply tank and the spinning nozzle. A filter is placed in each of the lines. Double means for blocking the passage of the composition to the spinning head is provided in each of the lines. One blocking means is placed before and one after the filter. Closable passage means is also provided allowing the spinning composition to be passed from the filter to the atmosphere in order to check the effectiveness of a newly installed filter. The apparatus insures the continuity of the spinning process and insure that air inclusions, bubble formation, and the like, will not take place during the filter changing step.

The present invention relates in general to apparatus for spinning threads from viscous spinning compositions. More particularly, the invention is directed to apparatus wherein the spinning composition is conducted alternately in one of several parallel lines or line sections having therein a changeable filter insert to the spinning nozzle and wherein a blocking device is provided associated with each filter insert.

In order to assure a trouble-free spinning process it is necessary, among other things, to free the spinning composition of possible foreign bodies before its entry into the fine spinning nozzles. For this purpose there are installed in the feed lines of the nozzles, especially in artificial silk spinning machines, sieves, holes plates or filters, for example candle filters. Naturally, such filter devices gradually clog and must, therefore, be replaced from time to time. In changing the filter, however, the composition flow and thereby the spinning process are undesirably interrupted.

In order to eliminate this drawback it has been proposed that several filters be switched into the line parallel to one another in fixed position, whereby it is possible to operate without interruption of the composition flow. Through the use of many stopcocks which have to be operated in a certain sequence in the switching over, there exists, however, the danger of passing over of unfiltered spinning composition and of entry of air into the composition and thereby of interruption of the capillary thread emerging from the spinning nozzle. Another known device provides two candle filters standing opposite one another, of which the one is in active position and which, when the latter is fouled, are swung in common in such a way about a vertically standing and fixedly positioned cock plug that the other, clean filter moves into the active position, the fouled one automatically moving into a position in which, for the purpose of cleaning, it is subjected to a flushing back through purified spinning composition. With the aid of these known arrangements, however, it is 3,501,806 Patented Mar. 24, 1970 ice not possible to achieve any satisfactory results. Even if the interruption of the composition flow takes place only briefly it is not possible to avoid the result that the threads break off at the nozzle. This is due, on the one hand, to the fact that in the filter change or line change burned or decomposed spinning composition residues in melt spinning processes pass into the spinning nozzle. On the other hand, in all kinds of spinning processes during the changing of the filter device air forces its way into the line to the nozzle, mixes there with the spinning composition and forms in this composition small gas bubbles, which then, in turn, bring about the tearing off of individual fibers or at least lead to undesired form, color and light eifects in the threads.

The present invention, therefore, has as its principal objective providing apparatus which insures the continuity of the spinning process during the filter change while not jeopardizing the thread by air inclusions, bubble formation, and the like during the filter changing operation.

In order to achieve the above objective it is proposed according to the invention that the spinning composition, in the line change, first of all be conducted into the new line with a clean filter insert in each case while it continues to flow in the original line; then it is run off from the new line through an exit opening lying in each case before the last blocking device into the open until possible air or residue inclusions have passed off, and, finally, after opening of this block as well as after closing of the first block (obstacle) of the original line it is conducted solely through the new line. The advantage of this changing method lies in the fact that the filter change can be carried out at any time during the continuous spinning operation without fear of a breaking off of the threads. Furthermore, because the spinning composition at first in each case emerges into the open, it is possible to test the quality of the filtrate. It is possible, therefore, to be assured of the effectiveness of the clean filter before the path is freed for the spinning composition to travel to the spinning nozzle, so that it is made certain that only faultless filtered composition arrives at the nozzle.

For the execution of this process, it is proposed according to the invention, to arrange a closable discharge opening in each of the parallel lines between the two blocking devices in the zone of the exchangeable filter insert. Here, several parallel lines can be grouped together in one filter block with in each case an outlet opening arranged between the blocking devices.

Through the proposed measures it is possible in the spinning process to avoid carrying along burned or decomposed spinning composition residues in melt spinning processes and to avoid bubble formation resulting from the filter change in all kinds of spinning processes.

It is ovious that in the formation of the pasage branchings as Well as of the blocking members and emergence apertures in the zone of the parallel lines special care must be used in order to avoid niches and dead spaces in which spinning melt would accumulate and decompose. It is just as important, however, that the blocking members of the lines that are out of operation are so tight that the s inning composition which flows past the blocks and through the open line cannot force its way into gaps between the line walls and blocking members Where it could decompose.

An effective packing (sealing) is achieved, in a further embodiment of the invention, by providing hollow spaces in the blocking devices that are arranged to receive very nearly incompressible liquid or plastic materials. These materials are placed under pressure with the aid of suitable means, for example, by screws, which close the filling aperture of the hollow spaces, in such a way that they bring about an expansion of the wall material of the blocking members in its elastic range. In this manner the outside surfaces of the blocking member. are pressed against the inside walls of the lines to produce a perfect seal.

The temperature of the compositions conveyed in the lines is important in determining their flow characterlstlcs in passing through the filter devices. It is therefore further proposed that the lines be arranged so as to be heatable individually or in common in the zone of the blocking members and emergence apertures.

In the drawing there is schematically represented an example of an apparatus for the execution of the process.

FIG. 1 shows a section through the longitudinal axis of the spinning composition line in region of the parallel conduit sections of the filter block; and

FIG. 2 shows the section IIII according to FIG. 1, perpendicular to the central axis of the line.

The main line 1, of square or rectangular cross section, coming from the supply tank, is divided in the example shown into two partial passages at point 2, likewise of rectangular cross section, of which the one 3, 4- according to FIG. 1 is open and the other 3', 4' is closed by means of blocking slides 5 and 6. In the blocking members 5 and 6 there are arranged hollow spaces 7 and 8, which are filled, each over a threaded bore (not represented) with a liquid or plastic material and are closable by means of a screw (likewise not represented), which then, in turn, exerts such a high pressure on the material enclosed in the corresponding hollow space 7 or 8 that the blocking member, by reason of the elasticity of its wall material is pressed, with sealing effect on all sides, against the inside walls of the passage 3', 4'. By this means the penetration of spinning composition into the closed passage 3', 4' is avoided with certainty. In the line section 3, 4 and between the blocking members 5 and 6 there are seated the filter devices 9 and 10 with their sieve holes 11. According to FIG. 1 both lines 3, 4 and 3', 4' include in the zone of the filter insets 9 and 10 an outlet aperture 12. and 12', which, according to FIG. 2 is closable by the pin 13 of the screw 15 shiftable in the filter block 14. The off-flow tube 16 establishes the connection between the outlet opening 12 and the outer air. For the lateral limitation of the device there serve the side plates 17 and 18 fastened by means of a rapid-closing device, which simultaneously carry the heating bands 19 and 20. According to FIG. 2 blocking slide 5' of the line section 3 that is in operation extends so far out of the block 14 that its lower edge forms in the passage section 3 the upper passage inside wall of the latter. The passage 21 leads directly to the nozzle (not represented) During the spinning process the spinning composition flows through the line 1, 3, filter insert 9 and line 4, 21 to the nozzle. When the filter 9, because of fouling, has to be replaced by a clean one, first of all the pressure prevailing in the hollow space 7 is released by winding out the screw (not represented), then the blocking slide 5 is drawn out of the block 14 until its lower edge aligns with the upper side of passage 3'. After the blocking member 5 is arrested in this position by means of a device (not represented), the liquid enclosed in the hollow space 7 is again placed under pressure in order to seal the contact gaps between the blocking slide 5 and block 14 in the upper passage wall 3. On opening of this line section the spinning composition forcing its way along under the blocking slide 5 pushes the air that has forced its way in ahead of it, which then mixes in part with the spinning composition and forms undesired air bubbles. The spin- 4 ning composition permeated in this manner with air now flows through the sieve holes 11 of the filter device 10 and over the outlet aperture 12' represented in dot-and-dash lines, from which the pin (plug) 13 has been removed by turning screw 15, through the outlet tube 16 into the open.

Only when spinning composition of faultless quality emerges from the discharge tube 16 is the emergence opening 12 again tightly closed by means of the pin 13, the hollow space 8 of the blocking slide 6, until now standing under pressure, is relieved and the latter (slide) is drawn out of the block 14 until its lower face surface exactly closes oil? with the upper passage interior wall, exactly as that of blocking slide 5, and thereby, finally, the whole passage cross section is released for the spinning composition flow. Now line 3, 4 can be closed by means of a blocking slide (not represented) in section 4, which corresponds in its function to the blocking slide 6. After line section 3, 4 is finally blocked with blocking slide 5 indicated in FIG. 2, the filter insert 9 can be taken out of block 14 and in its place there can be placed a fresh or clean insert. Both the blocking members used for the blocking of line section 3, 4 likewise have hollow spaces filled with a liquid or plastic medium, which spaces are placed under pressure for the sure sealing of line 3, 4. In conclusion the side plates 17 and 18 removed at the beginning of the changing process, with their heating bands 19 and 20, are again mounted on the block.

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

The invention is hereby claimed as follows:

1. Apparatus for carrying viscous spinning composition which comprises: at least two parallel lines leading to the spinning nozzle; a changeable filter insert in each of said lines; blocking means associated with each of said lines for preventing the flow of spinning composition through each of said lines, said blocking means including a blocking member located before said filter in each of said lines and a blocking member located after said filter in each of said lines; and a closable outlet associated with each of said lines and located between said blocking members and after said filter for carrying 011 contaminated spinning composition.

2. Apparatus according to claim 1, characterized in that the blocking members contain hollow spaces for receiving substantially incompressible materials.

3. Apparatus according to claim 1 which includes heating means for the lines arranged in the zone of the block ing members and outlet aperture.

References Cited UNITED STATES PATENTS 2,184,177 12/1939 Burrell. 3,007,199 11/1961 Curtis. 3,033,256. 5/1962 Schrenk. 3,059,276 10/1962 'Yokana.

FOREIGN PATENTS 684,976 4/1964 Canada.

WILBUR L. McBAY, Primary Examiner US. Cl. X.R. 1812 

